Tamal Kṛṣṇa: "This indeed is actual freedom from all miseries arising from material contact. This yoga is to be practiced with determination and an undaunted heart."
Twenty-four: "One should engage oneself in the practice of yoga with undeviated determination and faith. One should abandon, without exception, all material desires born of ego and thus control all the senses on all sides by the mind."
Purport: "The yoga practitioner should be determined and should patiently prosecute the practice without deviation."
Prabhupāda: Now, this determination can be, I mean, actually practiced or can be actually attained by one who does not indulge in sex life. His determination is strong. Therefore in the beginning it was said that without sex life, the determination. Or controlled sex life. If you indulge in sex life, then this determination will not come. Flickering determination. You see? Therefore the sex life should be controlled or given up. If it is possible to give up altogether; if not, controlled. Then you'll get determination. Because after all, this determination is bodily affair. So these are the methods how to get determination.